Madigan will wear the number 10 jersey for his country against the minnows as Joe Schmidt's side aim to make it two wins out of two in the tournament on Sunday.
Madigan, who came off the bench in the Pool D opener, says it's a "dream" to start for Ireland.
He told Ireland's official website: "It's a big lift but I don't use selection to compare myself to other players. I view it as an opportunity for myself to start a game in a World Cup.
"It's a dream of mine to be presented with this opportunity. If I had been picked to come off the bench, or I wasn't selected to be in the 23, then I'd deal with that on an individual basis. I wouldn't be looking at who is starting."
He added: "It's about what I can control and, for me, that's going out and leading the team around the pitch and doing my best to make the players around me look as good as possible."